JPH10313454A - Digital video image distribution system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital video image distribution system, easy for extension and with reduced maintenance cost for re-installation, that is built up with due consideration to real time performance of a video image and is operated as a component of a LAN. SOLUTION: A system is provided with a means that uses a transmitter side terminal equipment 102 to convert an analog video signal of a video source into digital information by video information compression, a means (hub 103) that distributes the digital video information to a plurality of destinations by a multi-cast communication packet, and a means (NIC included in 104) having an address filter for an address denoting a transmission source to a network interface of a receiver side terminal equipment 104. Then an address denoting the transmission source of the multi-cast communication packet is set to the address filter from a host processing side. Thus, a load of a CPU of the receiver terminal equipment is relieved, the number of terminal equipments sending a video image operated simultaneously is limited only by information amount to be contained in a LAN and a video image information amount, and the system has extendability (coping with increase in input and output numbers).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital video distribution apparatus for simultaneously distributing analog video signals from a plurality of transmission sources as digital video information to a plurality of receiving terminal apparatuses, and more particularly to a local area network (hereinafter, referred to as LAN) connection. Using the multicast communication means, the number of receiving terminal devices can be increased without the influence of an increase in communication load, the delay of distribution processing is small, and the receiving terminal device for receiving a plurality of transmitted digital video information is used. The present invention relates to a digital video distribution device that reduces the processing load on the CPU and simplifies wiring connection between terminal devices.

[0002] Further, there is provided a digital video distributing apparatus capable of reproducing video information for a predetermined period of time from the occurrence without any loss in obtaining video information when an abnormality occurs for some reason.

[0003] The term "video" in the present invention includes, in principle, audio that is combined with a video.

[0004]

2. Description of the Related Art FIG. 12 shows a configuration example of a conventional video distribution apparatus. In FIG. 1, reference numeral 1 denotes a video source, which includes a camera, a microphone, and the like. 2 is a control line, 3 is a video line, 4
Is a video distributor, 5 and 6 are routing switchers, 7
Denotes a receiving device, 8 denotes a control unit, and 9 denotes a broadcasting device.

The conventional video distribution apparatus shown in FIG. 12 is a video source 1 such as a camera and a microphone which is distributed in a remote place via a video line 3 and a monitor device for confirming a monitor which is disposed in the premises and a main line for broadcasting. Consists of equipment. The monitoring device is a switching type unidirectional analog routing switcher 5
The signal between the devices is mainly composed of the video signal and the audio signal from the camera side, and the control signal to the camera is divided into separate switchers. It requires large-scale wiring facilities.

In order to select a desired video source at the receiving devices 7 arranged at various places in the premises, a remote controller of the receiving device 7 instructs the control unit 8 of the routing switcher 5 to make a selection, and in accordance therewith. The control unit 8 uses the matrix control signal of the routing switcher 5 and switches both signals so that the video signal and the audio signal are transferred to the receiving device 7 in order to further control the camera. Is realized.

[0007] The main line equipment for broadcasting takes out the video signal and the audio signal in parallel with the above-mentioned monitor confirmation by the video distributor 4 and, based on the result of the monitor confirmation, the digital routing switcher 6 of the main line equipment. One broadcast content is selected and connected to the broadcasting device 9.

As another form of wiring to a receiving device for monitor confirmation, a cable broadcast (CAT) using a coaxial cable is used.
V), but it is basically an analog system and there are few bidirectional information transfers.

When a LAN is used for digital video distribution, it is necessary to have a high-speed information transfer which ensures low-delay real-time performance without disturbing the received video, and an optical cable type asynchronous transfer mode suitable for multimedia communication. (Hereinafter referred to as ATM) has become mainstream and expensive.

[0010]

In the conventional system,
There are the following problems.

In order to increase the number of video sources and receiving-side devices, it is necessary to add an additional routing switcher or a matrix switch unit that is a component thereof, and also to add wiring for each signal. And the cost burden was large. Furthermore, in the case of a routing switcher, the information transfer is unidirectional, and the transfer of control information for controlling the video source from the remote controller of the receiving device cannot be performed by the same wiring, and the wiring equipment is different for each signal, so that a large scale is required. And it was complicated.

[0012] In the case of an optical cable type ATM used as a LAN in the conventional digital video distribution, high-speed information transfer is required to smoothly pass a plurality of video information, and the hardware is expensive and the optical cable is expensive. Wiring was not easy either.

Conventional LA for Computers
N IEEE802.3 LAN devices (carrier sense multiple access / collision detection system, hereinafter CSMA / CD)
The communication method is a shared bandwidth type, and when a collision occurs in data transmission, a retransmission wait occurs after a random time. When video data is simultaneously transferred from a plurality of locations, a transfer delay occurs and the data is reproduced. The image is distorted. That is, in the case of video communication, a real-time property that does not allow a delay or fluctuation in transfer is required. This is because the time from the moment one piece of data arrives as the fate of the picture data until the next piece of picture data arrives depends on the number of frames per unit time of the original picture,
If this interval is not maintained, the reproduced video will be degraded from the original video quality. That is, unlike an office computer environment system which has an allowance in real-time performance, a video processing apparatus may significantly deteriorate video quality unless time management is properly performed.

Therefore, an object of the present invention is to provide a LAN hub connection without using a routing switcher of a monitor device at least without using a routing switcher of a main line device according to usage. LAN for computers
It is an object of the present invention to construct a device in consideration of the real-time property that cannot be considered, that is, various problems on the time axis, and to operate as a video distribution device successfully. It is another object of the present invention to provide a video distribution device that can be constructed with a small facility cost, requires less operation and maintenance costs such as a change in an installation location, and can easily cope with an expansion. It is another object of the present invention to reduce the load on the CPU in the receiving process and to enable the accumulation and reproduction only before and after a certain trigger.

[0015]

In order to achieve these and other objects, the present invention has the following configuration as one form.

1. In a device for distributing a plurality of video images of a plurality of destinations simultaneously among a plurality of video terminal devices connected in a local area network, an analog video signal of a video source is converted into digital video information by video information compression at a transmitting terminal device. Means (ENCs of 102-1 to 102-n), means (103 hub) for distributing the digital video information to a plurality of destinations by a multicast communication packet, and an address of an address indicating a transmission source to the network interface device of each receiving terminal device Means including a filter (901 in FIG. 10)
(Register & collation), means for setting the address indicating the source of the multicast communication packet in the address filter from the upper processing (901 register in FIG. 10 and FIG. 1)
10, 1001 register 1), means for setting only a multicast communication packet having an address indicating a transmission source set in the address filter as valid reception information (90 in FIG. 10).
1 collation and 1003 collation circuit of FIG. 11), and means (DEC of 104-1 to 104-n) for converting effective reception information into an analog video signal by video expansion at the receiving terminal device. Video distribution device.

2. In the configuration described in the above item 1, furthermore, a means for accumulating valid reception information in a memory at the receiving terminal device (602RAM in FIG. 7), a means for judging stop of accumulation (program processing of the 601 CPU in FIG. 7), and a storage and reproduction A digital video distribution device comprising: a skip-back means (program processing of the CPU 601 in FIG. 7).

In order to achieve the above-mentioned object, the present invention provides a method for bidirectional data transfer by connecting each device to a LAN.
Voice and control signals are realized using the same cable. Also, as a digital video distribution device (broadcasting station specification), for the first time, the ISO standard IS13818 and the ITU-T Recommendation H.264 which require high image quality and a small amount of transfer information according to the broadcasting station specification are required.
262 (hereinafter referred to as MPEG2) digital video compression / expansion was applied. In order to secure a low delay (300 milliseconds or less) in the video compression / expansion, a combination of a simple profile and a main level (hereinafter referred to as SP @ ML) is selected from profiles and levels defined in the standard.

In the video compression / expansion method, even if the increase in the amount of information is allowed, high quality is ensured and the delay is further reduced. A motion JPEG method corresponding to the use of only one frame defined by MPEG2 may be applied.

The LAN system includes IEEE802.12
-Type LAN device (Demand Priority Communication System, hereinafter referred to as 100VG-AnyLAN) communication hub with high speed of 100Mbps and round-robin LAN
Control (collisionless LAN) is applied. The video distribution between the LAN-connected terminal devices is a multicast communication that is one-to-many distributed communication.

The video information distributed via the hub by the multicast communication is transmitted to the network interface device (hereinafter, referred to as NIC) of the receiving terminal device from the distributed plural pieces of video information by hardware of a lower layer. By filtering out only desired one video information in advance, unnecessary video information is eliminated, and the upper C
Reduce the processing load on the PU.

For the LAN wiring, an unshielded 4-pair twisted pair cable (hereinafter referred to as 4-UTP) was applied in view of ease of construction of the physical medium and price.

[0023]

According to the present invention, analog video signals collected from various locations are digitally compressed by a transmitting terminal device, a plurality of digital video information are transmitted by multicast communication which is a one-to-many distributed communication by connecting each terminal device to a LAN. At the same time, distribution is performed, and the desired one piece of digital video information is decompressed and returned to analog video information by the receiving terminal device.

According to such a configuration, 100 VG-A
The speed / performance ratio of the LAN portion of the nyLAN can be realized about 5 times as compared with the same 100 Mbps CSMA / CD-LAN communication system.

By using MPEG2 standard digital video compression / expansion, one video of TV broadcast quality at a fixed bit rate can have a fixed information amount of about 6 Mbps. For this reason, it is possible to multiplex a plurality of videos in a 100 Mbps bandwidth of 100VG-AnyLAN.

For video distribution between LAN terminal devices, one-to-many multicast communication is used, and transmission to the LAN is performed in comparison with the case where one-to-one unicast communication distributes packets for the number of destinations. The amount of information does not increase.
That is, the transmitting side terminal device does not need to repeatedly perform the transmission operation for the destination, and the processing load and the processing delay do not increase.

[0027] Even if the number of receiving terminal devices is increased in the same segment, the effect of increasing the information amount of the LAN is small.
It is only necessary to limit the number of ports provided in the hub (including cascade connection) to be used and the connection distance.

The required processing capability of the receiving terminal device is as follows:
Even if the number of video sources increases, only one video source filtered by the NIC is required. Therefore, it is expected that the processing load can be reduced to the simultaneous processing of other application software and the software decoding processing of a future video.

The number of connections of the transmitting terminal device is 100 VG-
It can be determined by the amount of information accommodated in consideration of the transmission efficiency in the AnyLAN segment and the total amount of information of each video, and the maximum number that can be used can be designed in advance. There is no delay.

In the receiving terminal device, in addition to real-time video reproduction, by storing desired digital video information in a memory, video reproduction can be easily performed later.

[0031]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a digital video distribution apparatus according to the present invention.

FIG. 1 is a block diagram showing the overall configuration.

In FIG. 1, reference numeral 20 denotes a video source;
Is a control line, 110 is a video line, 101 is a video distributor,
102 is a transmitting terminal, 103 is a hub, 104 is a receiving terminal, 105 is a routing switcher, 106
Is a pre-matrix, 107 is a control server, 108 is a communication server, and 111 is a broadcasting device.

An example of a digital video distribution apparatus having a LAN configuration in a broadcasting station will be described. An analog video signal (hereinafter, including a microphone audio signal) from a plurality of cameras is transmitted to a video line 1
10 to the video distributor 101 by relaying,
In addition to synchronizing with intra-station synchronization, the digital signal is sent to a video compression device (hereinafter referred to as ENC) of the transmission side terminal device 102, where it is digitized and information compressed. Assembled into a packet having a multicast address and an IP multicast address, and a hub 10 of 100 VGAny-LAN.
3 and is distributed to the receiving-side terminal device 104. That is, a plurality of pieces of digital video information are simultaneously distributed to a plurality of receiving-side terminal devices 104 for monitoring confirmation of arrangement in each studio or the like. The NIC of the receiving-side terminal device 104 receives and processes only digital video information packets having a desired IP source address and IP multicast address from digital video information packets multicast-transmitted from the transmitting side. This packet is transferred to a video decompression device (hereinafter DEC).
) And returns it to an analog video signal (including audio as well as video) and outputs it to the monitor. And / or store it in a memory, and output and output the image later.

The transmitting terminal device 102 and the receiving terminal device 1
In the configuration of No. 04, one personal computer may be used for each piece of video information, or a plurality of video information may be handled by one personal computer. In this example, one personal computer is used for each piece of video information, and the number of personal computers is n.

For program broadcasting, an analog video signal obtained by the receiving terminal device 104 is used and transmitted to the broadcast equipment 111. Alternatively, when the digital video compressed / expanded information is not used for program broadcasting, the camera video signal is branched to another route for monitoring via the video distributor 101 as in the conventional case,
Any video information may be selected for broadcasting by the routing switcher 105 while the monitor is confirmed by the receiving side terminal device 104. A portion surrounded by a dotted line in FIG. 1 shows such a state.

The camera is installed at the transmitting terminal 10.
It may be in a LAN that can be directly connected to the second personal computer or in a remote place. In the case of a remote place, an ultra-high-speed dedicated TV line or a microwave line is used for the video line 110 for communication of a camera video signal. A low-speed public communication line (telephone network, ISDN) or a dedicated line is used for the control line 109 for the camera control signal such as the camera focus, brightness, and the direction of the camera platform because the information amount is small. If the number of cameras installed is larger than the number of ENCs of the transmitting terminal device 102, a pre-matrix 106 is added to select a camera video signal, and matching with the transmitting terminal device 102 is achieved.

In the camera control, a source video selection operation and an instruction operation such as a focus, a brightness, and a direction of the camera control are performed from each remote controller of the reception-side terminal device 104, and the instruction operation is performed via the LAN as a control signal. Do with. The remote control of the receiving side terminal device 104 is a dedicated box and can be configured with a designation switch, a joystick, or the like.
Keyboard and mouse inputs from the window screens 04-1 to 104-n may be used. Here, the control signal is once relayed by connecting the control server 107 to the hub 103 so that instructions from a plurality of receiving terminal devices 104 are not simultaneously issued to one camera. Tell the camera. The control server 107 ignores the control from the other until the previously received one ends so as not to control one or more cameras at the same time. The method of transmitting the control signal from the control server 107 to the camera depends on the connection form between each transmitting terminal device 102 and the camera, from the control server 107 to the camera directly connected to each transmitting terminal device 102, or separately from the communication server 108. Public communication lines (telephone network, ISD
N) or control line 109 of a dedicated line is used. That is, control signals are collected from the receiving-side terminal device 104 to the control server 107 via the LAN hub 103, and the camera is controlled via the communication server 108 and the control line 109 via the LAN hub 103. Alternatively, the information is transmitted from the control server 107 to the directly connected camera. Further, the transmitting terminal device 1
2 to the camera (shown in FIGS. 2 and 6).

In this embodiment, the control server 107 and the communication server 108 are shown as separate devices, but they may be integrated.

The operation result of the camera control is confirmed by monitoring the image transmitted from the camera.
Since this feedback loop system is used, a series of information transfer and processing delays occur in confirming the operation result, and if the delay time increases, smooth operation cannot be performed. The delay time allowed for human operation is about 300 milliseconds, which can be kept within the range by applying the present invention.

The transmitting terminal 102 and the hub 1 shown in FIG.
03. Configuration of the receiving-side terminal device 104.

The transmitting terminal 102, the hub 103, and the receiving terminal 10 of the overall configuration shown in FIG.
The configuration of No. 4 is shown in correspondence with the 33rd Commercial Broadcasting Technology Report Meeting in the literature.

The transmitting terminal 102 is connected to the personal computer PC1 <
102-1> and PC2 <102-2>, and the receiving terminal device 104 is a personal computer PC3 <104-1>, PC2.
4 <104-2>. PC1 <1
02-1> comprises encoders ENC, NIC and other basic parts of a personal computer. The personal computer PC3 <104-1> is composed of decoders DEC, NIC and other basic parts of the personal computer. NTSC is an analog video signal. The CTL is a control signal, which passes through another communication server 108 in the example of FIG. 1, but corresponds to information of RS-232C in the example of FIG. 6 described later.

The principle of hub operation which is a feature of the 100 VGAny-LAN shown in FIG.

In the operation of the hub 103, the 100 VGAny-LAN has a demand priority (a packet which is critical in time is set to a high priority, a normal data packet is set to a normal priority, and a normal priority is set when the high priority is lost).
N has priority in passing packets) and round-robin arbitration LAN control (device 30 to which hub 103 is connected)
1 to the device 30n are sequentially scanned for high-priority transmission, and if there is no transmission, normal-priority transmission is sequentially scanned. At one time, only one packet is received and transmitted from the other, It is characterized by collisionless LAN (which does not cause collision).

In the present invention, the setting of the operation for the hub 103 is such that a packet of digital video information which is time-critical is set to a high priority, and a control signal of the camera is a normal data packet of a normal priority. In this case, since the high priority digital video information is preferentially received and sent out from the other, the distribution capability can be designed in advance only with the digital video information, and the total digital video information amount greatly changes in time series. Nothing happens. That is, there is no need to cause a delay that disturbs the image at the time of distribution.

For example, when 6 Mbps digital video information is multiplexed at 100 Mbps, 12 video can be distributed simultaneously with a transfer efficiency of 75% (transfer capacity is said to be 96% or more) with a margin.

If the amount of control signal information of the camera is small and the total amount of digital video information is more than the transfer capacity of the LAN, a difference in priority is given to the digital video information and the control signal of the camera. Instead, both may be normal priority or high priority.

On the other hand, when another computer device for data communication is connected to this LAN, it is accommodated as a normal priority having a low priority, so that digital video information is prioritized. Mixed use can be performed without inconvenience.

Priorities are set in advance for each NI
There is a case where it is fixed to C in terms of hardware, and a case where it is designated to the NIC according to data from the application.

In the LAN system, if the number of video source connections is small or the transmission capacity is large and a margin for video information distribution can be secured, the 100 VG described in this embodiment is used.
Although not necessarily limited to Any-LAN, CSMA /
It may be a CD or ATM, or 1G to be planned in the future
It may be a bit CSMA / CD-LAN.

The principle of multicast communication and addresses shown in FIG.

FIG. 4 is an enlarged view showing the contents of a packet.

In the multicast communication, the amount of information to be transmitted to the hub 103 in the LAN is equivalent to the one-to-one unicast communication even if the distribution is one-to-many multiple destinations. To achieve this, a multicast address is defined in the TCP / IP communication protocol. This is the IP of the outgoing packet
The destination is a specific IP multicast address, and the destination is a pair with the source IP source address. Furthermore, the destination of the MAC address is also a specific M
It is an AC multicast address, and is composed of a pair with the source MAC source address. The transmission-side apparatus 401 differs from ordinary unicast communication only in address processing using a specific value for the destination. When the hub 103 determines that the packet is a multicast communication packet from the address of the transmitted packet, the hub 103 simultaneously transmits the packet from another port while receiving the packet. If the receiving-side devices 402 to 40n are configured with only one segment as in this example, the receiving-side devices 402 to 40n may participate in the multicast communication at the discretion of the receiving-side devices 402 to 40n. That is, each of the receiving-side devices 402 to 40n may perform the packet receiving process by checking the destination MAC multicast address or IP multicast address. The transmitting side sequentially shifts each port in a round robin manner as shown in FIG. Each other port becomes a receiver.

If the LAN is composed of a plurality of segments, a router (not shown) used between the segments
From this, procedures such as inquiring each connected device to participate in multicast communication and responding to the connected device are used, and routers do not perform multicast communication on segments without connected device to participate, so that there is no invalid communication. ing.

FIG. 6 shows the configuration of the transmitting terminal device 102 shown in FIG.

The transmitting terminal 102 is a personal computer 102
The CPU and the memory unit are added to the −n main board, and ENC and NIC are added to the host bus as an expansion board. The control signal CTL for direct connection camera control is provided by the RS-232 provided as standard equipment in the personal computer 102-n.
By connecting from the port C, the control server 1
07.

The analog video signal NTSC from the camera is input to the ENC directly or via a video line, digitized and compressed to obtain digital video information, and the digital video information is temporarily stored in the memory section of the main board. Thereafter, the packet is transferred to the NIC and is used as a multicast communication packet using a 4-UTP cable.
Sent to. At this time, the audio information is transmitted in combination with the video information in accordance with the rules of MPEG2.

In MPEG2 of TV broadcast quality, at present, it is difficult to perform video compression / expansion processing by software, and the hardware ENC is used. This ENC has SP
ＥＮ Use ENC of low-delay video compression that applies I / P frames in accordance with the rules of ML. Further, as a format of a stream of digital video information, a transport stream (TS) mode of a fixed-length format capable of performing a subsequent recovery operation even if an error occurs during communication is used.

If the standard of the main level (MP @ ML) of the main profile defined in the MPEG2 is used, a combination of I / P / B frames is used.
There is a delay on the order of seconds before playback output. That is, the use of the B frame is a bidirectional predictive coded image, and the use of the B frame causes a large delay in the compression / decompression processing.

In the SP @ ML applied here, a combination of I / P frames is used, and a video of 30 frames per second can be reproduced with a delay of about 270 milliseconds for 8 frames including delays from compression to communication and decompression. .

In order to ensure high quality and reduce delay even when the amount of information increases, video compression / expansion is performed using another video compression method, such as MPEG-2, which is independent between frames.
Motion JPEG equivalent to using only one frame
The system may be used.

FIG. 7 shows the configuration of the receiving terminal device 104 shown in FIG.

The receiving terminal device 104 is a personal computer 104
The CPU 601 and the memory unit are added to the -n main board, and the DEC and the NIC are added to the host bus as an extension board. Also, a separate ring buffer RAM 6
02 may be added. The DEC is connected to a video playback monitor or a live broadcasting device. Also, the operation unit of the remote controller is connected to the control unit.

The packet received from the LAN hub 103 is received by the NIC via a 4-UTP cable, temporarily stored in the memory section of the main board, passed to the DEC, returned to the original analog video signal NTSC, and transmitted to the broadcast equipment. Or output to the monitor. Audio is also processed in combination with video.

For storing digital video information for later video reproduction or skip back, a part of the above-mentioned memory unit or a magnetic disk device provided in a personal computer or a semiconductor rewritable nonvolatile memory or a silicon disk provided separately. Select from and configure.

Configuration of communication server 108 shown in FIG.

The communication server 108 includes a CPU, a memory unit, and a plurality of RS-232C (or RS-42
2) Multi-port card MPC having interface
And NIC are added. Multi-port card M
A communication control unit CC composed of a terminal adapter is connected to the PC in the case of a telephone network or a modem in the case of ISDN.

The received packet from the LAN hub 103 is received by the NIC, and a control signal is transmitted from the corresponding RS-232C (or RS-422) port on the camera side. This is a communication control unit CC consisting of a modem or a terminal adapter.
The camera and its camera platform are controlled via the communication line 109.

Configuration of control server 107 shown in FIG.

The control server 107 has a configuration in which a CPU and a memory unit are added to a main board of a personal computer, and a multi-port card MPC and an NIC are added to a host bus as an expansion board. The reception of the camera control signal and the transfer control via the communication server 108 are performed by software processing included therein. The multi-port card MPC is connected to an upper personal computer that controls the entire system when it is used. Further, when the pre-matrix 106 is added, it is connected to the multi-port card MPC, and the selection instruction is processed therefrom.

The hardware and address filter of the NIC shown in FIG.

The NIC is connected to the hub 103 of the LAN and the LA
The N controller performs 100 VGAny-LAN communication processing, and transfers information between the memory in the NIC and the memory unit on the main board side via the host bus. This information transfer employs a bus master type high-speed data transfer method. In other words, the NIC itself performs direct memory access (DMA) transfer of information between its memory and the memory unit on the main board side by the host bus controller, thereby achieving C
High-speed data transfer with reduced dependence on PU processing.

The NIC hardware address filter selects a valid packet in advance from packets having an information amount proportional to the number of transmission sources received by multicast communication from the LAN hub 103, and the subsequent processing load Add to reduce. This is realized by selecting only packets having a valid source address from received packets. This process is called NIC
It is implemented as a hardware function. That is, NI
A register & collation 901 is provided in C, and an IP multicast address to be validated and an IP source address of a transmission source are set in a register according to designation from the CPU side of the upper processing, and an IP multicast address and a transmission source IP of each received packet are set. Compares source addresses and discards packets that do not match as a result of the comparison. The matching packet is stored in the memory in the NIC and sent to the memory unit on the main board side via the host bus.

FIG. 11 shows the operation of the register & collation 901 in FIG. The register & collation 901 is connected to the LAN controller, and is a register 1 (1001) for storing a valid IP multicast address and a source IP source address designated by the CPU for higher-level processing.
And a register 2 (1002) for setting an IP multicast address extracted from a received packet and an IP source address of a transmission source, and a collation circuit (1003) for collating contents between the two registers. Matching results match,
The mismatch is returned to the LAN controller. If they do not match, the LAN controller discards the received packet.

If the IP multicast address uses a unique value for each ENC of the transmission-side terminal device 102, the IP multicast address is not the IP multicast address and the source IP source address, but the IP multicast address. May be used alone.

The hardware configuration of the NIC is NIC
When the internal processing is controlled by a newly added CPU (not shown), the same filter processing may be performed by firmware processing of the CPU without providing the register & collation 901 circuit.

Other Embodiments Modifications such as changing the video source to be distributed to video information stored not only in the camera but also in the video server, and changing the graphic user interface of the user for the remote controller in the receiving terminal device according to the contents of the application. By doing so, the present invention can be applied to CATV and VOD in a hotel, a remote lesson system, an on-premise lesson broadcast system, and the like.

When a video line relays a video signal of a camera located at a remote place through a microwave line shared with a fixed station or a mobile station for other relay applications, the number of video relays that can be used simultaneously is limited. . In order to achieve this effective use, video compression / decompression for monitor confirmation is performed in accordance with other ITU Recommendation H.264. 261 or MPEG-1
The control line used for the camera control may be set to the amount of information that can also be used for video signal transfer, and the monitor confirmation of the present invention may be performed via the control line, so that only the video line for camera video for broadcasting is used. This is because the transmitting terminal device 102 and the receiving terminal device 104 in FIG.
The EC is used only for broadcasting (as a result, the DEC of MPEG2 can be reduced for monitoring), and the video compression / expansion function of the simple system described above is added to each device.
By doing so, it is possible to monitor only the use of relaying the broadcast video on the microwave line with the video of the simple system and select only the selected video. In other words, there is no need to use a microwave line for monitor confirmation, and only those used for the main line for broadcasting will use the microwave line.
Efficient use when sharing microwave links with fixed and mobile stations.

At the same time as the installation of the camera, a signal generator for generating a keep-alive signal indicating that the camera can be operated periodically or an abnormality notification signal (triggered by detection of an earthquake, abnormal change in image content, etc.) is installed (see FIG. 2) From now on, a signal is transmitted in the opposite direction to the camera control signal, and the communication server 10
8 for receiving the signal, and transmitting the signal to the same multicast communication or unicast communication as the video signal (reception-side terminal device 1).
04 when the subsequent processing is performed by the specific device). In some or specific personal computers of the receiving terminal device 104,
A ring buffer RAM is provided as storage memory, and digital video information is cyclically overwritten and stored in the ring buffer RAM. Here, the digital video information of 6 Mbps requires a capacity of about 50 MB for one minute of storage, so that a ring buffer RAM having a capacity larger than the interval between keep-alive signals or a capacity corresponding to the time to be acquired may be prepared. By adding this configuration, the receiving-side terminal device 104 determines that the periodic keep-alive signal from the corresponding signal generation device has been interrupted, or receives an abnormal notification signal (earthquake notification, abnormal change in image content, etc.). Then, the notification of the stop of the video accumulation is determined. As a result, it is possible to provide a skip-back function that enables accumulation and reproduction only before and after the change point on the camera side without causing a gain loss. With this configuration, it is possible to effectively realize sudden event monitoring such as when an earthquake occurs at the camera installation location. The ring buffer RAM may be newly added to the personal computer. In addition, a memory unit, a magnetic disk device, or the like already provided in the personal computer may be extended and used. In the case of using the conventional video tape apparatus, the tape operation starts from the time of detecting the abnormality, and there is a delay in the rise of the tape, so that the acquisition loss of the video information is caused. However, this configuration can solve the problem.

[0081]

As described above, according to the present invention, the load on the CPU of the receiving terminal device is reduced, and the number of simultaneously operating terminal devices that transmit video is limited only by the information capacity of the LAN and each video information volume. In other words, it has a scalability (corresponding to an increase in the number of inputs and the number of outputs) even though it has a simple configuration that has never been seen before.

The wiring between the terminal devices is easy, and the installation and maintenance costs for expansion and relocation are small.

The present invention is not limited to a video transmission / distribution apparatus and an abnormal monitoring and recording system in a broadcasting station, but also uses a video server as a video source to be transmitted in addition to a camera. It can be used in other applications, such as:-CATV, VOD, video check-out terminal, etc.-Karaoke BOX-Remote teaching system for school education or broadcasting system on campus .

[Brief description of the drawings]

FIG. 1 is a block diagram showing the overall configuration of the present invention.

FIG. 2 is a block diagram showing a core part of the configuration of the present invention and showing configurations of a transmitting terminal device, a hub, and a receiving terminal device.

FIG. 3 is a diagram showing a hub operation of 100 VGAny-LAN.

FIG. 4 is an enlarged view of a packet.

FIG. 5 is a diagram showing multicast communication and addresses;

FIG. 6 is a diagram showing a configuration of a transmission-side terminal device 102;

FIG. 7 is a diagram illustrating a configuration of a receiving-side terminal device 104;

FIG. 8 is a diagram showing a configuration of a communication server 108;

FIG. 9 is a diagram showing a configuration of a control server 107.

FIG. 10 is a diagram showing NIC hardware and an address filter.

FIG. 11 is a diagram showing an operation of a register & collation 901;

FIG. 12 is a diagram showing a conventional configuration example.

[Explanation of symbols]

 Reference Signs List 20 video source 109 control line 110 video line 101 video distributor 102 transmitting terminal device 103 hub 104 receiving terminal device 105 routing switcher 106 pre-matrix 107 control server 108 communication server 111 broadcasting equipment

Claims (2)

[Claims] An apparatus for simultaneously distributing a plurality of video images of a plurality of destinations among a plurality of video terminal devices connected in a local area network, wherein an analog video signal of a video source is compressed by a transmitting terminal device by video information compression. Means for making digital video information, means for distributing the digital video information to a plurality of destinations by a multicast communication packet, means for providing an address filter of an address indicating a transmission source to a network interface device of each receiving terminal device, and multicasting for the address filter Means for setting an address indicating a transmission source of a communication packet from a higher-order process, means for setting only a multicast communication packet having an address indicating a transmission source set in the address filter as valid reception information,
Means for converting the effective reception information into an analog video signal by video expansion at the receiving terminal device. 2. A means for converting an analog video signal of a video source into digital video information by compressing video information at a transmitting terminal, a means for distributing the digital video information to a plurality of destinations by a multicast communication packet, Means for providing the network interface device with an address filter of an address indicating a transmission source, means for allowing the address filter to set the address indicating the transmission source of the multicast communication packet from a higher-order process, and indicating the transmission source set in the address filter A plurality of video terminals connected in a local area network, comprising: means for converting only valid multicast information having an address into valid reception information; and means for converting the valid reception information into an analog video signal by video expansion at a receiving terminal device. A device that distributes multiple images to multiple destinations simultaneously among devices 2. A digital video distribution apparatus according to claim 1, further comprising: means for accumulating valid reception information in a memory in the receiving terminal device, means for judging storage stop, and means for skipping back accumulation / reproduction.